Jillian Michaels Says She's Going to Sue Netflix, Bob Harper, Dr. Huizenga Over 'Biggest Loser' Doc

Jillian Michaels is coming out swinging -- telling TMZ the entire 'Biggest Loser' documentary is a giant lie ... and she’s already lawyering up.

The celeb trainer says she’s meeting today with powerhouse attorney Bryan Freedman to plot her next move -- which could include going after Netflix, the producer of the doc, Bob Harper, and Dr. Robert Huizenga in court.

Jillian isn’t stopping there either ... she points out Brandon Riegg -- the exec who bought the doc for Netflix -- was one of the top dogs at NBC during the last several seasons of "The Biggest Loser." Translation: he knew exactly what went down behind the scenes.

As for the claims she was sneaking contestants caffeine pills ... Jillian tells us that’s bogus, and she’s got the receipts.

She says she’s sitting on numerous emails -- several of which she showed in an IG post Tuesday -- proving caffeine was always approved on the show -- just like Ambien and smokeless tobacco, which she personally refused to use.